The present invention relates to the field of internal combustion engines and, more particularly, to electrically-actuated components in the fuel systems of internal combustion engines.
Internal combustion engines are used in a variety of applications, such as lawnmowers, generators, pumps, snow blowers, and the like. Such engines usually have fuel tanks coupled thereto to supply fuel to the engine through a supply line. It is desirable to reduce emissions from devices powered by internal combustion engines. Even when the engine is not being used, the engine can release emissions of hydrocarbons or gasoline resulting from daily ambient temperature changes. Such emissions are known as xe2x80x9cdiurnalxe2x80x9d emissions.
To help reduce emissions from the engine, it is known to provide internal combustion engines with fuel shutoff devices that block the flow of fuel to the engine upon engine ignition shutdown. Without such a shutoff device, fuel is wasted, and unburned fuel is released into the environment, thereby increasing hydrocarbon exhaust emissions. Likewise, the presence of unburned fuel in the combustion chamber may cause dieseling. When the engine is not operating, pressure buildup in the fuel tank caused by increased ambient temperatures can force fuel into the engine, where the fuel can be released into the atmosphere.
It is also desirable to reduce emissions from the fuel tank. Fuel tanks are typically vented to the atmosphere to prevent pressure buildup in the tank. While the engine is operating and drawing fuel from the fuel tank, the vent in the fuel tank prevents excessive negative pressure inside the tank. While the engine is not operating (i.e., in times of non-use and storage), the vent prevents excessive positive pressure that can be caused by fuel and fuel vapor expansion inside the tank due to increased ambient temperatures. Fuel vapors are released to the atmosphere, primarily when a slight positive pressure exists in the tank.
One common method of venting fuel tanks includes designing a permanent vent into the fuel tank cap. Typically, the fuel tank is vented via the threads of the screw-on fuel tank cap. Even when the cap is screwed tightly on the tank, the threaded engagement does not provide an air-tight seal. Therefore, the fuel tank is permanently vented to the atmosphere. Another method of venting fuel tanks includes the use of a vent conduit that extends away from the tank to vent vapors to a portion of the engine (i.e., the intake manifold) or to the atmosphere at a location remote from the tank.
The present invention provides a fuel vent closure device that is actuated automatically by the operation of a manually-operable engine control device such as a deadman or bail lever, a start/stop device such as a button, knob, or key, or a speed control device. In other words, the engine control device, which is already coupled to the ignition circuit to selectively stop and/or start the engine, is also coupled to the vent closure device so that no additional action on behalf of the operator is required to actuate the vent closure device. In fact, the operator may not even know that the manual operation of the engine control device simultaneously actuates the vent closure device.
When the engine control device is remotely located from the engine and the fuel tank (as is the case with a deadman or bail lever on the handle of a walk behind lawnmower), the automatic actuation of both the ignition switch and the vent closure device preferably occurs from a remote location. Linkage assemblies such as bowden cables, levers, cams, and other members, are preferably used to remotely actuate the ignition switch and an electrical actuator coupled to the vent closure device. The electrical actuator may be an electric stepper motor, an electric wax motor, a solenoid, and the like, that is electrically connected to a power source. A power source, such as a battery or magneto, is used to power the electrical actuator.
In one aspect of the invention, the engine control device and the fuel vent closure device are also coupled to an automatic fuel shutoff device that blocks the flow of fuel to the internal combustion engine when the engine stops. Preferably, the single action of manually operating the engine control device causes actuation of each of the vent closure device, the fuel shutoff device, and the engine ignition system. Again, if the engine control device is remote from the engine and the fuel tank, linkages are used to remotely actuate the ignition switch and the electrical actuator or actuators used to actuate the vent closure device and the fuel shutoff device. In a preferred embodiment, a single valve assembly acts as both the fuel vent closure device and the fuel shutoff device, and a single electrical actuator actuates the valve.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description and drawings.